The field of sensors encompasses a wide variety of materials and devices used
for capturing physical, chemical or biological stimuli converting them to
measurable output signals. Nanomaterials may be used as active sensing elements
or receptors, as transducing components (e.g. electro- or chemo-mechanical
actuators), and even as electrodes in electronic circuitry and power systems
for Nanomaterials and Sensor Development at the State University of New York at
Stony Brook which the author established in 2003 and she still directs,
specializes on the synthesis and use of nanomaterials: metal oxides,
electro-active polymers, their composites, and their hybrids with biomolecules
(enzymes, peptides), primarily as active elements of bio-/chemical sensor
systems. Nanomaterials are very important to resistive chemosensing2, a key transduction mode in which chemical or biochemical
signal inputs induce changes in the electrical resistance of the active
Since gas adsorption on the sensor materials' surfaces is fundamental to the
resistive gas detection process, reducing the dimensionality of the sensor
materials to the nanoscale, thus increasing their surface to volume ratio, has
the obvious effect of improving gas sensitivitya. Numerous reports in
the literature have documented several orders of magnitude increases in the gas
response of nanomaterials compared to their bulk(ier) counterparts1,3. The response and recovery time of
nanomaterials-based chemiresistors may be impressively as low as
a increasing the amplitude of
change of the electrical resistance of the active element in the presence of the
same concentration of the gas
bsingle crystal metal oxide nanowires of "extreme"
aspect ratio were synthesized by Professor Gouma's research group by means of
c the use of nanotechnology for the early detection,
prevention and cure of diseases
Professor Gouma's research group has made unique contributions
to establishing and explaining the gas specificity observed in functional metal
oxide nanomaterials, such as TiO2, MoO3 and
WO3. Using a crystallo-chemical approach, it is shown that the phase
of the nanomaterial (crystallographic polymorph) rather than it's chemical
composition, is the critical parameter controlling the affinity of a
stoichiometric metal oxide to a specific gaseous analyte4,5. For example, both the â-phase of
MoO3 and the ã-phase of WO3 are selective to nitric oxide
(NO), because both share the cubic rhenium trioxide structure6. This is not the case with the a-phase of MoO3-
having a unique, open orthorhombic crystal structure- that serves as a highly
selective ammonia detector7.
Interestingly, there is a little-known phase of the WO3 material
that is ferroelectric and makes an excellent acetone detector8. This phase is thermodynamically stable below -40°C9. Thanks to the availability of nanomanufacturing
processes10, Professor Gouma's research group was able to stabilize this
nanophase to RT and to use it for sensing11. This
"novel" nanomaterial, å-phase WO3, interacts with polar gases through
a dielectric poling sensing mechanism8,11, a true breakthrough in gas sensing.
As nanoscale synthesis of metal oxides favors metastability12, there is a toolbox of "rare" phases now available to
gas detection and monitoring, including hexagonal WO3, anatase and
brookite TiO2, to name a few. Furthemore, processing these
"gas-selective" oxide phases in 1D nanowire configurationsb adds
improved sensitivity to gas specificity13, thus
detection limits of only a few gas molecules (ppb levels) of signaling
metabolites have been achieved recently1-3. This
finding has important implications for nanomedicinec applications of
Among the successful nanotechnologies that The Center for
Nanomaterials and Sensor Development at the State University of New York at
Stony Brook has pioneered, single breath analysis diagnostics stand out.
Electronic Olfaction14 (whether it is electronic
nose or tongue technologies), has been limited by the lack of selective sensors
to discriminate gases in a complex gas environment (such as breath odor).
Figure 1. Ceramic
oxide nanoparticles that are used as sensing elements in a breathanalysis device
prototype (shown above) that monitors selectively the concentration of a gaseous
biomarker for diabetes monitoring in a non-invasive manner (copyright: P. Gouma,
The nanomaterials-based sensors described above offer inexpensive
alternatives to costly and bulky optical detectors, the main competing selective
gas sensing technology under development15. On/off
nanosensor devices have been demonstrated that may detect from bacterial
infection to diabetes, and even lung cancer16.
Using bio-doped nanostructured oxides (urease in MoO3)17 or bio-nanocomposites (PANI/CAionophores/
peptides)18 as sensing elements, further expands
the scope of using nanomaterials as resistive biosensors in non-invasive
In summary, nanomaterials are having a tremendous impact in sensing
applications as they offer improved selectivity, sensitivity, and rapid response
to the bio-/chemical analytes of interest. Resistive chemosensors using
nanomaterials have enabled novel inexpensive and non-invasive applications for
health and safety, such as breath analyzers, sweat test diagnostics, and other
personalized medicine and protection tools. Selfpowered nanosensor devices
relying completely on hybrid nanowire technology are envisioned for the near
1. P. Gouma, Nanomaterials for Chemical
Sensors and Biotechnology, Pan Stanford Publishing, 2009.
2. P. Gouma, D. Kubinski, E. Comini, and V. Guidi, eds,
"Nanostructured Materials and Hybrid Composites for Gas Sensors and Biomedical
Applications", Materials Research Society, Warrendale, PA, Spring 2006.
3. G. Shen, P-C. Chen, K. Ryu, and C. Zhou,
"Devices and Chemical Sensing Applications of Metal Oxide Nanowires, Journal of
Materials Chemistry, 19, pp. 828-839, 2009.
4. P.I. Gouma, A.
K. Prasad, and K.K. Iyer, "Selective Nanoprobes for Signaling Gases",
Nanotechnology, 17, pp. S48-S53, 2006.
5. P. I. Gouma,
"Nanostructured Polymorphic Oxides for Advanced Chemosensors", Rev.Adv. Mater.
Sci., 5, pp. 123-138, 2003.
6. P.I Gouma and K.
Kalyanasundaram, "A Selective Nanosensing Probe for Nitric Oxide", Appl. Phys.
Lett., 93, 244102, 2008.
7. A.K. Prasad, D. Kubinski, and P. I.
Gouma, "Comparison of Sol-Gel and RF Sputtered MoO3 Thin Film Gas
Sensors for Selective Ammonia Detection", Sensors & Actuators B, 9,
8. Lisheng Wang, "Tailored Synthesis and
Characterization of Selective Metabolitedetecting Nanoprobes for Handheld Breath
Analysis", Ph.D. thesis, SUNY Stony Brook, Dec 2008.
Matthias and E.A. Wood, "Low temperature polymorphic transformation in
WO3". Phys. Rev., 84(6), pp. 1255-1255, 1951.
K. Wegner and S.E. Pratsinis, "Nozzle-quenching process for controlled flame
synthesis of titania nanoparticles", AICHE J., 15, pp. 432-436, 2003.
11. L. Wang, A. Teleki, S.E. Pratsinis, and P.I. Gouma,
"Ferroelectric WO3 Nanoparticles for Acetone Selective Detection",
Chem. Mater., 20(15), pp. 4794- 4796, 2008.
12. H. Zhang, H.
and J.F. Banfield, "Understanding polymorphic phase transformation behavior
during growth of nanocrystalline aggregates: Insights from TiO2",
Journal of Physical Chemistry B, 104, pp. 3481-3487 2000.
P. Gouma, K. Kalyanasundaram, and A. Bishop, "Electrospun Single Crystal
MoO3 Nanowires for Bio-Chem sensing probes", Journal of Materials
Research, Nanowires and Nanotubes special issue, 21(11), pp. 2904-2910,
14. P. Gouma and G. Sberveglieri, "Novel Materials and
Applications of Electronic Noses and Tongues", MRS Bulletin, 29 (10), pp.
15. M.R. McCurdy, Y. Bakhirkin, G. Wysocki, R.
Lewicki, and F.K. Tittel, "Recent Advances in Laser-spectroscopy-based
Techniques for Applications in Breath Analysis", J. Breath Res., 1, 014001, pp.
16. P. Gouma, K. Kalyanasundaram, X. Yun, M.
Stanacevic and L. Wang, "Chemical Sensor and Breath Analyzer for Ammonia
Detection in Exhaled Human Breath", IEEE Sensors, Special Issue on Breath
Analysis, 10 (1), pp. 49-53, 2010.
17. S.Y. Gadre and P.
Gouma, "Biodoped Ceramics: Synthesis, Properties And Applications", J. Amer.
Ceram. Soc. - Invited Feature Article, 89 (10), pp. 2987- 3002, 2006.
18. A. S. Haynes and P.I. Gouma, "Electrospun Conducting
Polymer-based Sensors for Advanced Pathogen Detection", IEEE Sensors Journal,
8(6), pp. 701-70, June 2008.
Copyright AZoNano.com, Professor Perena Gouma (State University
of New York (SUNY) Stony Brook )